The purpose of this project is to apply recombinant DNA and cloning technology to the isolation and analysis of genomic DNA sequences involved in the regulation of globin gene expression in humans and animals. Fragments of DNA relating to globin and thymidine kinase gene expression in humans and/or animals are isolated from genomic clones (constructed in this and other laboratories) and subcloned into plasmids for use in studies on eukaryotic gene expression. A prokaryote-eukaryote-prokaryote DNA transfer and recovery system has been developed which is proving useful in studying the regulation of gene expression in eukaryotes.